I generally don't have battery problem, it lasts for few days, but then again I don't do much. But last night I used wifi for no more then 20 minutes(I always disconnect and it isn't on auto connect or anything) and it drained 20% of my battery. Is that supposed to happen? I went to bed and after like 9 hours it didn't move even 5%, almost straight line. So if I used wifi for like 2 hours it would drain completely?